Why in the news?

• A study shows heat-related deaths among India’s elderly rose by 55% between 2000–04 and 2017–21, with states like Uttar Pradesh and Rajasthan worst affected.

Heatwave

• Definition: Heatwaves are prolonged periods of excessively hot weather that can cause adverse impacts on human health, the environment, and the economy.
• Criteria to declare
  • Plains: At least 40°C (104°F)
  • Hilly regions: At least 30°C (86°F)
  • Coastal Areas: maximum temperature is 37°C
• Causes for Heatwaves
  • Trapped Hot Air: High-pressure systems can act like a lid, trapping warm air near the Earth’s surface and preventing cooler air from rising and replacing it.
  • Lack of Cloud Cover: With minimal cloud cover, more solar radiation reaches the ground, intensifying the heating effect.
  • Global Warming: The average global temperature is rising due to greenhouse gas emissions.
  • Urban Heat Island Effect: Cities tend to be hotter than surrounding rural areas.
• Impacts of heatwaves
  • Human Health: Heatstroke, dehydration, heat exhaustion, worsening of pre-existing conditions (respiratory, heart), especially for vulnerable populations (elderly, children, outdoor workers).
  • Infrastructure: Increased strain on power grids due to air conditioning use, and potential for power outages. Damage to roads and railways.
  • Environment: Increased risk of wildfires, drought conditions due to excessive evaporation, and damage to crops and ecosystems.
  • Social and Economic Impacts: Reduced work productivity, disruption of transportation, increased strain on emergency services.